With an intermediate transfer body or a photoconductor (which may be a belt, a roller, etc.) that is a belt-shaped image bearer used in an electrophotography-type image forming apparatus, a sheet may twine around the image bearer due to electrostatic adsorption force of the sheet onto the image bearer or curling of the sheet for toner to be transferred onto the sheet. When the apparatus is further operated while the sheet is twined around the image bearer, the sheet may get into the apparatus and, in the worst case, a component damage, etc., may occur. Therefore, it is known to provide a sheet twining prevention structure which prevents the sheet from getting into the apparatus when the sheet twines around the image bearer.
More specifically, a technique is known such that a separation claw which includes functions of contacting with and separating from a belt is provided to suppress deterioration of a toner image forming face as well as to ensure that a printing medium is peeled off a toner image forming face and the separation claw is abutted against a transfer belt for a short time at which a leading edge of the sheet is peeled off the transfer belt and damage to the belt is suppressed to a minimum level (see Patent Document 1, for example).